JP4770590B2 - Outline creation apparatus, creation method, and image processing apparatus - Google Patents

Description

  The present invention relates to an outline creation apparatus, an outline creation method, and an image processing apparatus that create an outline that indicates a boundary between first and second level regions of a still image. Specifically, the present invention corresponds to a pixel at each edge position having a level between the first and second levels, and based on the data values of the edge position and surrounding pixels, the first and second pixels in the pixel. Concerning outline creation devices that can create outlines with real number accuracy, not pixel units, by generating boundary lines that indicate the boundaries of level regions and obtaining the outlines by connecting the generated boundary lines It is.

Conventionally, in the field of image processing, detection of the edge position of a still image has been performed for various purposes. For example, in Patent Document 1, as a method of encoding image data at a high compression rate, instead of encoding the image data itself, the edge of the image data is continuously detected and the continuous edge data is encoded. It is described that. Further, for example, in Patent Document 2, when an overlay state of a circuit pattern is inspected using an overlay mark during manufacturing, an edge position (mark position) is detected from a captured image of a CCD camera. ing. This edge position is detected by, for example, detecting a portion where the pixel data value changes rapidly.
JP-A-8-36641 JP 2004-79970 A

  In the edge position detection described in Patent Document 1 and Patent Document 2 described above, the edge position is detected in units of pixels. However, when this edge position is an outline indicating the boundary between the black level region and the white level region, for example, considering the image enlargement process by increasing the number of pixels, it is desirable to detect the edge position in units smaller than the pixel unit. It is.

  An object of the present invention is to make it possible to create an outline with real number accuracy instead of pixel units.

The concept of this invention is
An edge detection unit that detects a pixel at an edge position having a level between a first level and a second level greater than the first level from each pixel constituting the still image;
A pixel cutout unit that cuts out the pixel at the edge position and the pixel located around the pixel at the edge position corresponding to the pixel at each edge position detected by the edge detection unit;
Corresponding to each pixel at each edge position detected by the edge detection unit, based on the data value of the pixel extracted by the pixel extraction unit, the first level region and the second level in the pixel A boundary line generation unit for generating a boundary line indicating a boundary with the level region;
The boundary lines generated by the boundary line generation unit corresponding to the pixels at the respective edge positions detected by the edge detection unit are connected, and the first level region and the second level in the still image are connected. and a link unit for obtaining the outline indicating a boundary between the level of the region,
The boundary line generation unit
A boundary angle detector that detects the angle of the boundary based on the difference between the data value of the pixel at the edge position and the data value of the pixel located in the periphery;
A boundary line for detecting the intercept of the boundary line of the angle detected by the boundary line angle detection unit based on the mixing ratio of the first level and the second level corresponding to the data value of the pixel at the edge position Consisting of a section detector,
The pixel cutout unit
Cut out pixels d2 and d1 that are adjacent to the pixel at the edge position in the horizontal direction and pixels d3 and d4 that are adjacent to the pixel at the edge position in the vertical direction;
The boundary angle detection unit is
Outline generating apparatus, characterized in that shall be the horizontal component d2-d1 and angular directions 90 degrees by adding angular boundaries of the difference vector of the vertical component d4-d3.

  In the present invention, the pixel at the edge position having a level between the first level (for example, the black level) and the second level (for example, the white level) is detected from the data of each pixel constituting the still image. The detection of the edge position is performed in units of pixels. In the present invention, an outline indicating the boundary between the first level region and the second level region is further created with real number accuracy using the pixels at the respective edge positions. Here, each of the first and second levels means a certain level or a level having a predetermined width.

  That is, corresponding to each pixel at each edge position, the pixel at this edge position and the pixels located in the vicinity thereof are cut out, and based on the data values of these pixels, the first level region and the second region in the pixel are extracted. A boundary line indicating the boundary with the region of the level is generated.

  In this case, for example, the angle of the boundary line is detected based on the difference between the data value of the pixel at the edge position and the data value of the pixel located in the vicinity thereof. Further, based on the mixing ratio of the first level and the second level corresponding to the data value of the pixel at the edge position, the above-described angle-detected boundary line intercept is detected. Here, the intercept refers to the coordinates of the intersection point with the pixel frame of the boundary line. The position of the boundary line on the pixel is specified by this intercept.

  The boundary lines generated corresponding to the pixels at the respective edge positions are connected to obtain an outline indicating the boundary between the first level region and the second level region in the still image. For example, the direction of the boundary line corresponding to the pixel at each edge position is set such that a pixel with a high data value exists on the left side or the right side, and the second boundary line connected to the first boundary line is the first boundary line. It is assumed that the boundary line has the start point closest to the end point of one boundary line.

  As described above, the first and second level regions in the pixel corresponding to the pixel at each edge position having a level between the first and second levels, based on the data value of the edge position and the surrounding pixels. A boundary line indicating the boundary is generated, and then each boundary line is connected to obtain an outline, and an outline is created with real number accuracy instead of pixel units.

  For example, still image data with an increased number of pixels is generated based on the outline thus created. In this case, since the boundary between the first level region and the second level region in the still image is indicated with real number accuracy by the generated outline, the level is the first level in the outline portion when the number of pixels is increased. The number of pixels that are intermediate values between the level and the second level can be reduced, and an enlarged image with a clear outline can be obtained.

  According to the present invention, corresponding to the pixel at each edge position having a level between the first and second levels, the first and second pixels in the pixel are based on the data values of the edge position and the surrounding pixels. A boundary line indicating the boundary of the level region is generated, and the generated boundary lines are connected to obtain an outline, and an outline can be created with real number accuracy instead of pixel units.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration of an image processing apparatus 100 as an embodiment. The image processing apparatus 100 includes a CPU (Central Processing Unit) 101, a ROM (Disk Read Only Memory) 102, a RAM (Random Access Memory) 103, an image memory 104, a user operation unit 105 such as a mouse or a keyboard, A scanner 106, a camera 107, a display 108, and a printer 109 are configured by being connected to a bus 110.

  The CPU 101 controls the operation of the entire apparatus. The ROM 102 stores programs and data necessary for the operation of the CPU 101. The RAM 103 constitutes a work area of the CPU 101 and the like. The scanner 106 and the camera 107 constitute a still image data input unit. The display 108 and the printer 109 constitute an output unit for still image data. Here, the still image data is monochrome image data composed of a plurality of pixel data, and each pixel data is 8-bit data having a value of 0 to 255, for example.

  In the image processing apparatus 100 shown in FIG. 1, still image data obtained by the scanner 106 or the camera 107 is processed by the CPU 101 in response to a user operation by the user operation unit 105. Then, the processed still image data is supplied to the display 108 or the printer 109 and displayed or printed.

  Here, as the processing of the CPU 101 for still image data, processing for enlarging an image is performed. In this image enlargement process, the number of pixels corresponding to the image area to be enlarged is increased in accordance with the enlargement ratio in accordance with the enlargement ratio designated by the user operation. For example, when the enlargement ratio is 2, a 1/2 image area is set as an enlargement target, and the number of pixels corresponding to the image area is doubled.

  The CPU 101 constitutes an outline creation unit and a data generation unit in order to perform this image enlargement process. The outline creation unit obtains a boundary between the black level area as the first level and the white level area as the second level based on the still image data before processing stored in the image memory 104. . Further, the data creation unit increases the number of pixels in the image region to be enlarged based on the outline created by the outline creation unit, and generates still image data for the enlarged image.

  FIG. 2 shows functional blocks of the outline creation unit 200. The outline creation unit 200 includes an edge detection unit 201, a pixel cutout unit 202, a boundary line angle detection unit 203, a boundary line segment detection unit 204, and a connection processing unit 205. The boundary line angle detection unit 203 and the boundary line segment detection unit 204 constitute a boundary line generation unit.

  The edge detection unit 201 detects a pixel at an edge position having a level between the black level and the white level from each pixel constituting the still image. Here, a black level data value is “0”, a white level data value is “255”, and a pixel having a data value of “1” to “254” is detected as a pixel at an edge position. Note that the black level and the white level may have predetermined widths such as “0 to 10” for the black level and “245 to 255” for the white level.

  The image cutout unit 202 cuts out the pixel at the edge position and the pixels located in the vicinity thereof corresponding to each edge position detected by the edge detection unit 201. FIG. 3 shows a pixel structure of a still image. The pixels are arranged in a matrix so that the horizontal direction is N pixels and the vertical direction is M pixels.

FIG. 4A shows an example of a pixel to be cut out. In this case, the pixel d0 edge position, and the pixel d3, d4 respectively adjacent in the vertical direction perpendicular to the pixel d0, excised pixel d2, d1 respectively adjacent to the left and right horizontal direction with respect to the pixel d0 It is.

  The boundary line angle detection unit 203 corresponds to the pixel at each edge position, based on the difference between the data value of the pixel at the edge position and the data value of the pixel located at the periphery thereof, and a black level region in the pixel The angle of the boundary line indicating the boundary between the white level region and the white level region is detected. In this case, as shown in FIG. 4B, the horizontal direction component d2-d1 (= d2-d0 + d0-d1) and the vertical direction component d4-d3 (= d4-d0 + d0-d3) are 90 degrees in the direction of the difference vector VC. The angle obtained by adding only (shown by the wavy arrow) is the angle of the boundary line.

  As shown in FIG. 4C, the boundary line intercept detection unit 204 corresponds to the pixel at each edge position, and based on the black level and white level mixing rate corresponding to the data value of the pixel at the edge position, The intercept of the boundary line at the angle detected by the detection unit 203, that is, the coordinates (xs, ys), (xe, ye) of the intersection with the pixel frame of the boundary line are detected. In this case, the area ratio between the black level region Sb and the white level region Sw of the square pixels partitioned by the boundary line is set to a value corresponding to the above-described mixing ratio of the black level and the white level.

  Thus, a boundary line BL indicating the boundary between the black level region and the white level region in the pixel is generated corresponding to each pixel at each edge position. This boundary line BL indicates the boundary between the black level region and the white level region in the pixel at the edge position. Note that the direction of the boundary line BL is set so that pixels with a high data value exist on the left side or the right side, in this embodiment, on the right side. At this time, as shown in FIG. 4C, the coordinates (xs, ys) become the start point of the boundary line BL, and the coordinates (xe, ye) become the end point of the boundary line BL.

  The connection processing unit 205 connects the boundary lines of the pixels at the respective edge positions generated by the above-described boundary line generation unit (the boundary line angle detection unit 203 and the boundary line intercept unit 204), thereby obtaining a black level region in the still image. An outline indicating the boundary between the white level region and the white level region is obtained. In this case, as shown in FIG. 5A, the second boundary line BL connected to the first boundary line BL is a boundary line having a start point closest to the end point of the first boundary line.

  In FIG. 5A, the end point of the first boundary line BL and the start point of the second boundary line BL are connected. However, the coordinates of these end points and start points often do not match. Therefore, in this connection processing stage, as shown in FIG. 5B, the midpoints of the two boundary lines BL to be connected are connected by a straight line BL ′. In this case, this straight line BL ′ constitutes an outline.

  The operation of the outline creating unit 200 shown in FIG. 2 will be described along the flowcharts of FIGS.

  FIG. 6 shows the processing procedure of the outline creation process. In step ST1, the process is started, and in step ST2, the boundary line BL corresponding to the pixel at each edge position is generated. Next, in step ST3, the boundary lines BL generated in step ST2 are connected to obtain an outline, and then the process is ended in step ST4.

  FIG. 7 shows details of the processing procedure of the boundary line generation processing in step ST2 of FIG. In step ST11, the process is started, and in step ST12, the upper left pixel d (0,0) on the screen is set as a target pixel (see FIG. 3). In step ST13, it is determined whether or not the target pixel is a pixel at the edge position. In this case, when the data value of the target pixel is a data value between the black level data value “0” and the white level data value “255”, the pixel is determined to be the pixel at the edge position.

  Here, a character image as shown in FIG. 9 will be described as an example of a still image. FIG. 10 is an enlarged view of a part of FIG. 9 (illustrated by an arrow P), and the attached numerical values indicate the data values of the respective pixels. In this example, pixels having data values of “65”, “233”, “29”, “201”, “2”, “138”, “63”, “225”, “12” “144” are The pixel at the edge position.

When the target pixel is a pixel at the edge position, in step ST14, the boundary line angle and the boundary line intercept are detected, and the boundary line of the target pixel is generated. First, the angle of the boundary line is detected based on the difference between the data value of the target pixel (the pixel at the edge position) and the data value of the pixel located in the vicinity thereof (see FIGS. 4A and 4B). For example, when a pixel whose data value is “138” indicated by an arrow Q in FIG. 10 is a target pixel, d0 = 138, d1 = 0 , d2 = 255, d3 = 2 , d4 = 255, The horizontal direction component d2-d1 = 255 of the difference vector VC, the vertical direction component d4-d3 = 253 of the difference vector, and the angle of the boundary line is an angle of approximately 45 degrees to the lower right as indicated by an arrow R in FIG. It becomes.

  Next, the intercept of the boundary line is detected based on the black level and white level mixing rate corresponding to the data value of the pixel of interest (the pixel at the edge position) (see FIG. 4C). For example, when a pixel whose data value is “138” is the target pixel, 46% of black level “0” is mixed and 54% of white level “255” is mixed. Therefore, the intercept is detected so that the area ratio between the black level region Sb and the white level region Sw of the square pixel is 46:54.

  After the process of step ST14, the process proceeds to step ST15. If the target pixel is not a pixel at the edge position in step ST13, the process immediately proceeds to step ST15. In step ST15, it is determined whether or not the next pixel exists in the raster order. Here, the raster order is the pixel structure shown in FIG. 3, and d (0,0) → d (0,1) →... → d (0, N−1) → d (1,0) → d (1,1) → ・ ・ ・ → d (1, N-1) → ・ ・ ・ → d (M-2,0) → d (M-2,1) → ・ ・ ・ → d (M- 2, N−1) → d (M−1,0) → d (M−1,1) →... → d (M−1, N−1).

  When the next pixel exists, in step ST16, the next pixel is set as the target pixel, and then the process returns to step ST13 to perform the same processing as described above. On the other hand, when the next pixel does not exist, the process ends in step ST17.

  By performing the boundary line generation process according to the flowchart of FIG. 7, as shown in FIG. 12, boundary lines BL corresponding to the pixels at the respective edge positions can be generated.

  FIG. 8 shows details of the processing procedure of the boundary line connection processing in step ST3 of FIG. In step ST21, the process is started, and in step ST22, the upper left pixel d (0,0) on the screen is set as a target pixel (see FIG. 3). In step ST23, it is determined whether or not a boundary line exists in the target pixel. If there is a boundary line, it is determined in step ST24 whether the boundary line has been used in the connection process. If not used, the pixel of interest is set as a connected pixel in step ST25.

  Next, in step ST26, it is determined whether there is a boundary line that can be connected to the vicinity of the connection processing pixel, for example, an adjacent pixel. If there is a connectable boundary line, in step ST27, the boundary line of the connection processing pixel is connected to the boundary line having the start point closest to the end point. In step ST28, a used flag is set for the connected boundary line, a pixel having the boundary line is set as a connection processing pixel, and then the process returns to step ST26 to perform the same processing as described above.

  If there is no boundary line that can be connected in step ST26, a series of connection results are stored as shapes in step ST29, and then the process proceeds to step ST30. When the boundary line does not exist in the pixel of interest in step ST23, and when the boundary line has been used in step ST24, the process immediately proceeds to step ST30.

  In this step ST30, it is determined whether or not the next pixel exists in the raster order. When the next pixel exists, in step ST31, the next pixel is set as the target pixel, and then the process returns to step ST23 to perform the same processing as described above. On the other hand, when the next pixel does not exist, the process ends in step ST32.

  By performing the boundary line connection process according to the flowchart of FIG. 8, the boundary lines of the pixels at the respective edge positions can be connected, and an outline indicating the boundary between the black level and the white level in the still image is obtained with real number accuracy. Can be created. FIG. 13 shows an outline creation result corresponding to the still image of FIG.

  Next, a data creation unit that generates still image data for an enlarged image using the outline created by the outline creation unit described above will be described. In this data creation unit, when the enlargement ratio is ER, the 1 / ER image area is to be enlarged. For example, when ER = 2, 1/2 of the image area is an enlargement target. In this data creation unit, the number of pixels in the image area to be enlarged is increased ER times to generate still image data for the enlarged image. This enlargement ratio can be set independently in the horizontal and vertical directions.

  FIG. 14 shows functional blocks of the data generation unit 300. The data generation unit 300 includes a pixel number increase unit 301 and a data value determination unit 302. The pixel number increasing unit 301 increases the number of pixels in the horizontal direction and the vertical direction of the image area to be enlarged according to the enlargement ratio.

  The data value determining unit 302 determines the data value of each pixel after the increase in the number of pixels according to the position of the outline created by the outline creating unit. That is, the data value of a pixel that does not have an outline is determined as “0” when the pixel is in the black level region, and is determined as “255” when the pixel is in the white level region. Further, the data value of a pixel having an outline is determined according to the area ratio between the black level region and the white level region in the pixel. In this case, the data value increases as the ratio of the white level region increases.

  The processing operation of the data creation unit will be described with reference to FIG. FIG. 15A shows an example of a pixel before increasing the number of pixels. In the outline creation unit described above, pixels with data values “123” and “185” are edge position pixels, as shown in FIG. 15B. Then, an outline indicating the boundary between the black level “0” region and the white level “255” region is created. In the data generation unit, first, as shown in FIG. 15C, the number of pixels in the horizontal direction and the vertical direction is increased according to the set enlargement ratio. Then, as shown in FIG. 15D, the data value of each pixel is determined according to the position of the outline.

  According to the image processing apparatus 100 shown in FIG. 1, the outline creation unit 200 (see FIG. 2) configured by the CPU 101 corresponds to a pixel at each edge position having a level between a black level and a white level. Based on the edge position and the data values of the surrounding pixels, a boundary line BL indicating the boundary between the black level region and the white level region in the pixel is generated (see FIG. 4), and the generated boundary lines are connected. The outline can be obtained (see FIG. 5), and the outline can be created with real number accuracy instead of pixel units.

  Further, according to the image processing apparatus 100 shown in FIG. 1, the data generation unit 300 (see FIG. 14) configured by the CPU 101 increases the number of pixels in the image area to be enlarged at the set enlargement rate, and then outlines the outline. The data value of each pixel is determined based on the outline created by the creation unit 200 (see FIG. 15), and the outline indicates the boundary between the black level region and the white level region in the still image with real number accuracy. Therefore, the number of pixels whose level is an intermediate value between the black level and the white level in the outline portion when the number of pixels increases can be reduced, and an enlarged image with a clear outline portion can be obtained.

  For example, FIG. 16B shows the data value of each pixel when the number of pixels is increased using only the pixel shown in FIG. 16A (same as the pixel shown in FIG. 15A) without creating the outline as shown in FIG. 15B. As shown, the number of pixels having a data value between “0” and “255” in the outline portion is larger than that shown in FIG. 15D.

FIG. 17B is an enlarged image corresponding to the image of FIG. 17A (corresponding to FIG. 15A and FIG. 16A), and is based on the still image data for the enlarged image generated using the outline after it has been created. The outline is a clear enlarged image. On the other hand, FIG. 18B is an enlarged image corresponding to the image of FIG . 18A (corresponding to FIGS. 15A and 16A), and is based on still image data for an enlarged image generated without creating an outline. Yes, the outline is unclear and blurred.

  In the above-described embodiment, an example has been shown in which an outline indicating a boundary between a black level and a white level in a still image is obtained. However, the present invention is generally higher than the first level and the first level. An outline indicating the boundary with the second level can be obtained in the same manner.

  In the above-described embodiment, the outline is created and used in the image enlargement process. However, the outline created in this way can be used for other applications such as scanner technology. is there.

  The present invention can create an outline with real number accuracy instead of pixel units, and can be applied to an image processing apparatus or the like that performs image enlargement processing.

It is a block diagram which shows the structure of the image processing apparatus as embodiment. It is a block diagram which shows the functional block of an outline creation part. It is a figure which shows a pixel structure. It is a figure for demonstrating the detection process of a boundary line angle and a boundary line intercept. It is a figure for demonstrating the connection process of a boundary line. It is a flowchart which shows the process sequence of a boundary line preparation process. It is a flowchart which shows the process sequence of a boundary line production | generation process. It is a flowchart which shows the process sequence of a boundary line connection process. It is a figure which shows an example of a still image. It is the figure which expanded a part of still image and showed the pixel of an edge position. It is a figure which shows the relationship between a difference vector and a boundary line angle. It is the figure which showed the boundary line produced | generated by each edge position pixel. It is a figure which shows the creation result of an outline. It is a block diagram which shows the functional block of a data generation part. It is a figure for demonstrating the process of a data preparation part. It is a figure which shows the data value of each pixel when the number of pixels is increased without creating an outline. It is a figure which shows an example of the enlarged image by outline creation. It is a figure which shows an example of the enlarged image by outline non-creation.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Image processing apparatus, 101 ... CPU, 102 ... ROM, 103 ... RAM, 104 ... Image memory, 105 ... User operation part, 106 ... Scanner, 107 ... -Camera, 108 ... Display, 109 ... Printer, 110 ... Bus, 200 ... Outline creation unit, 201 ... Edge detection unit, 202 ... Pixel cutout unit, 203 ... Border Line angle detection unit, 204 ... Boundary line segment detection unit, 205 ... Connection processing unit, 300 ... Data generation unit, 301 ... Pixel number increase unit, 302 ... Data value determination unit

Claims (4)

An edge detection unit that detects a pixel at an edge position having a level between a first level and a second level greater than the first level from each pixel constituting the still image;
A pixel cutout unit that cuts out the pixel at the edge position and the pixel located around the pixel at the edge position corresponding to the pixel at each edge position detected by the edge detection unit;
Corresponding to each pixel at each edge position detected by the edge detection unit, based on the data value of the pixel extracted by the pixel extraction unit, the first level region and the second level in the pixel A boundary line generation unit for generating a boundary line indicating a boundary with the level region;
The boundary lines generated by the boundary line generation unit corresponding to the pixels at the respective edge positions detected by the edge detection unit are connected, and the first level region and the second level in the still image are connected. and a link unit for obtaining the outline indicating a boundary between the level of the region,
The boundary line generation unit
A boundary angle detector that detects the angle of the boundary based on the difference between the data value of the pixel at the edge position and the data value of the pixel located in the periphery;
A boundary line for detecting the intercept of the boundary line of the angle detected by the boundary line angle detection unit based on the mixing ratio of the first level and the second level corresponding to the data value of the pixel at the edge position Consisting of a section detector,
The pixel cutout unit
Cut out pixels d2 and d1 that are adjacent to the pixel at the edge position in the horizontal direction and pixels d3 and d4 that are adjacent to the pixel at the edge position in the vertical direction;
The boundary angle detection unit is
Outline generating apparatus, characterized in that shall be the horizontal component d2-d1 and angular directions 90 degrees by adding angular boundaries of the difference vector of the vertical component d4-d3. The connection processing unit
The direction of the boundary line corresponding to the pixel at each edge position generated by the boundary line generation unit is set so that pixels with high data values exist on the left side or the right side, respectively.
The outline creating apparatus according to claim 1, wherein the second boundary line connected to the first boundary line is a boundary line having a start point closest to an end point of the first boundary line. An edge detection step of detecting a pixel at an edge position having a level between a first level of each pixel constituting the still image and a second level larger than the first level;
A pixel cutout step of cutting out the pixel at the edge position and the pixel located around the pixel at the edge position corresponding to the pixel at each edge position detected in the edge detection step;
Corresponding to each pixel at each edge position detected in the edge detection step, based on the data value of the pixel extracted in the pixel extraction step, the first level region and the second level in the pixel A boundary generation step for generating a boundary line indicating a boundary with the level region;
Corresponding to each pixel at each edge position detected in the edge detection step, the boundary line generated by the boundary line generation unit is connected to connect the first level region and the second level in the still image. and a connecting process steps for obtaining the outline indicating a boundary between the level of the region,
The boundary generation step is
A boundary angle detection step for detecting an angle of the boundary line based on a difference between a data value of a pixel at the edge position and a data value of a pixel located at the periphery; and
A boundary line for detecting the intercept of the boundary line of the angle detected in the boundary line angle detection step based on the mixing ratio of the first level and the second level corresponding to the data value of the pixel at the edge position Section detection step,
In the pixel clipping step,
Cut out pixels d2 and d1 that are adjacent to the pixel at the edge position in the horizontal direction and pixels d3 and d4 that are adjacent to the pixel at the edge position in the vertical direction;
In the boundary angle detection step,
Outline generating method, characterized in that you angle obtained by adding 90 degrees in the direction of the difference vector comprised of the horizontal component d2-d1 and the vertical direction component d4-d3 and the angle of the boundary line. A data input unit for inputting still image data composed of a plurality of pixel data;
Outline creation for creating an outline indicating a boundary between a first level region and a second level region larger than the first level in the still image based on the still image data input to the data input unit And
Based on the outline created by the outline creation unit, a data generation unit that increases the number of pixels of the image region to be enlarged and generates still image data for the enlarged image,
The outline creation part
An edge detection unit for detecting a pixel at an edge position having a level between the first level and the second level from each pixel constituting the still image;
A pixel cutout unit that cuts out the pixel at the edge position and the pixel located around the pixel at the edge position corresponding to the pixel at each edge position detected by the edge detection unit;
Corresponding to each pixel at each edge position detected by the edge detection unit, based on the data value of the pixel extracted by the pixel extraction unit, the first level region and the second level in the pixel A boundary line generation unit for generating a boundary line indicating a boundary with the level region;
The boundary lines generated by the boundary line generation unit corresponding to the pixels at the respective edge positions detected by the edge detection unit are connected, and the first level region and the second level in the still image are connected. and a link unit for obtaining the outline indicating a boundary between the level of the region,
The boundary line generation unit
A boundary angle detector that detects the angle of the boundary based on the difference between the data value of the pixel at the edge position and the data value of the pixel located in the periphery;
A boundary line for detecting the intercept of the boundary line of the angle detected by the boundary line angle detection unit based on the mixing ratio of the first level and the second level corresponding to the data value of the pixel at the edge position Consisting of a section detector,
The pixel cutout unit
Cut out pixels d2 and d1 that are adjacent to the pixel at the edge position in the horizontal direction and pixels d3 and d4 that are adjacent to the pixel at the edge position in the vertical direction;
The boundary angle detection unit is
The image processing apparatus characterized by you angle obtained by adding 90 degrees in the direction of the difference vector comprised of the horizontal component d2-d1 and the vertical direction component d4-d3 and the angle of the boundary line.